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At least 649 records · Page 36Linked to original sources
PubMed1998

Activation of non-adrenergic non-cholinergic inhibitory pathways by endogenous and exogenous tachykinins in the ferret lower oesophageal sphincter.

Repeated oesophageal acidification causes lower oesophageal sphincter (LOS) relaxation in the anaesthetized ferret which is mediated by a peripheral neurokinin (NK-1) receptor mechanism. Our aim in this study was to characterize neural pathways in the LOS activated by capsaicin and tachykinin receptor agonists in vitro. Circular muscle strips of LOS (two per animal) from a total of 24 ferrets were maintained in organ baths. Electrical field stimulation (EFS, 50 V, 5-50 Hz) caused frequency-dependent LOS relaxation which was abolished by tetrodotoxin (TTX; 10(-6) M: P < 0.001) and reduced by N(G)-nitro-L-arginine (L-NNA; 10(-4) M: P < 0.01). Substance P and [Sar9, Met (O2)11]-substance P (selective NK-1 agonist) caused dose-dependent relaxation, while the NK-2 receptor agonist [beta-Ala8]-NKA 4-10 evoked excitation. Capsaicin (10(-6) M) caused relaxation and desensitization that was overcome by long recovery periods and substance P dosing (10(-8) M). After pretreatment with the NK-1 receptor antagonist CP 99994 (10(-7) M), substance P (10(-8) M; P < 0.001) and capsaicin (10(-6) M: P < 0.01)-induced relaxations were reduced. In the presence of TTX (10(-6) M), excitation resulted in response to substance P (10(-8) M; P < 0.05) and [Sar9, Met (O2)11]-substance P (10(-8) M; P < 0.001), while the response to [beta-Ala8]-NKA 4-10 (10(-7) M) was unaffected. In the presence of L-NNA (10(-4) M), substance P and [Sar9, Met (O2)11]-substance P-induced relaxations were reduced (10(-8) M; P < 0.01), while the response to [beta-Ala8]-NKA 4-10 (10(-7) M) was unaffected. These results show that functional coupling between capsaicin-sensitive sensory neurones and NANC inhibitory neural pathways occurs via NK-1 receptors in the ferret LOS. NK-2 (and some NK-1) receptors activate non-neural excitatory mechanisms. Substance P and NK-1 receptors coupling sensory and NANC inhibitory neurones may be important in the reflex control of LOS motility.

Animals↗
PubMed1998

Oesophagitis-induced changes in capsaicin-sensitive tachykininergic pathways in the ferret lower oesophageal sphincter.

Prolonged oesophageal acidification may impair lower oesophageal sphincter (LOS) function in reflux disease. The aim of this study was to investigate aspects of altered LOS innervation in a model of oesophagitis. Oesophagitis was induced by acid (HCl, 0.15 M) and pepsin (0.1% w/v) infusions in anaesthetized ferrets. LOS muscle strip responses to the following stimuli were measured in vitro from control and acid/pepsin-treated ferrets: electrical field stimulation (EFS; 1-50 Hz), potassium chloride KCl; 20 mM), substance P, [beta-Ala8]-neurokinin A 4-10, [Sar9, Met (O2)11]-substance P (all 10(-10) to 10(-6) M) and capsaicin (10(-8) to 10(-6) M). LOS relaxation occurred in response to all stimuli except [beta-Ala8]-neurokinin A 4-10, which evoked contraction. In muscle strips from acid/pepsin-treated animals there were no differences in amplitude or sensitivity of relaxation following EFS, KCl or substance P vs controls. However, the inhibitory response to capsaicin was increased four-fold (10(-8) M; P < 0.05) and an increased sensitivity of the inhibitory response to [Sar9, Met (O2)11]-substance P occurred (pD2 = 8.64 +/- 0.12 acid/pepsin-treated vs 7.94 +/- 0.24 control, P < 0.05). We conclude that in acute oesophagitis, increased sensitivity of capsaicin-activated inhibitory pathways occurs in which activation of NK-1 receptors plays an integral role in the ferret LOS.

Animals↗
PubMed2002

Lower oesophageal sphincter relaxation evoked by stimulation of the dorsal motor nucleus of the vagus in ferrets.

An understanding of the neural control of lower oesophageal sphincter (LOS) relaxation is clinically relevant because transient LOS relaxations (TLOSRs) are a mechanism of acid reflux into the oesophagus. Preganglionic motor neurones innervating the LOS are localized in the dorsal motor nucleus of the vagus (DMV). Based on a single study in cats, it is now widely accepted that these neurones are functionally organized into two separate populations, such that stimulation of the caudal and rostral DMV evokes LOS relaxation and contraction, respectively. Our goal was to map the functional LOS responses to chemical stimulation in the DMV and nucleus tractus solitarius (NTS) of ferrets, an animal model commonly used for conscious studies on TLOSRs, and to test whether DMV-evoked LOS relaxation is mediated through hexamethonium-sensitive vagal-inhibitory pathways to the LOS. We used miniaturized manometry with Dentsleeve to monitor LOS and oesophageal pressures in decerebrate unanaesthetized ferrets. LOS relaxation was evoked readily in response to gastric insufflation, which shows that the vago-vagal reflex was intact in this preparation. Microinjections of l-glutamate (12.5 nmol L-1 in 25 nL) were made into the DMV from approximately - 1.5 to + 2.0 mm relative to the obex. Microinjections into the caudal (- 1.5 to + 0.0 mm behind obex) and intermediate (+ 0.1 to + 1.0 mm rostral to obex) DMV both significantly decreased LOS pressure, and complete LOS relaxation was noted in 28/32 and 11/18 cases, respectively. LOS relaxation responses to DMV microinjection were highly reproducible and abolished by bilateral vagotomy or hexamethonium (15 mg kg-1 intravenously). A nitric oxide synthase inhibitor (l-NAME 100 mg kg-1 intramuscularly) significantly increased the time taken to reach the maximal response. Increases in LOS pressure (24 +/- 4 mmHg; n = 3) were obtained only when stimulation sites were located equal to greater than 1.5 mm rostral to the obex. LOS relaxation (- 78 +/- 10%; n = 6) was evoked by stimulation of the NTS but not immediately outside of the NTS (11 +/- 27%; n = 5). We conclude that there is a very extensive population of 'inhibitory' motor neurones in the DMV that may account for the predominant vagal-inhibitory tone in ferrets. As NTS stimulation evokes LOS relaxation and the predominant response to DMV stimulation is also LOS relaxation, this vago-vagal reflex may involve an excitatory interneurone between the NTS and DMV vagal inhibitory output.

Animals↗
PubMed1998

Spatial-frequency tuning and geniculocortical projections in the visual cortex (areas 17 and 18) of the pigmented ferret.

We have examined the spatial-frequency selectivity of neurons in areas 17 and 18 of the adult pigmented ferret, by measuring how the amplitude of response depends on the spatial-frequency of moving sinusoidal gratings of optimal orientation and fixed contrast. Neurons in area 17 of the ferret respond optimally to low spatial frequencies [average 0.25 cycles per degree (c/deg)], much lower than the optima for cat area 17. The tuning curves are of the same form as those found in cat and monkey: unimodal with bandwidths in the range 0.8-3.5 octaves. Neurons in area 18 of the ferret respond optimally to even lower spatial frequencies (average 0.087 c/deg) than area 17 neurons, and the distributions of optimal spatial frequency for areas 17 and 18 hardly overlap. In both cortical areas, the bandwidth of the tuning curves is inversely correlated with optimal spatial frequency. This marked difference in tuning between the two cortical areas is probably attributable to differential geniculo-cortical projections. Small injections of fluorescent latex microspheres or horseradish peroxidase (HRP) were made into area 17 or area 18 in order to investigate the populations of geniculate neurons projecting to the two cortical areas. After injections into area 17, labelled neurons are found predominantly in the geniculate A layers, with a few neurons labelled in the C layers. Conversely, after an area 18 injection, similar numbers of labelled neurons are found in the C layers as in the A layers. Soma-size analysis of the neurons in the A-layers suggests the existence of two populations of relay neurons, which project differentially to areas 17 and 18. The different geniculate inputs and the different spatial-frequency tuning in areas 17 and 18 may imply that the two cortical areas process visual information more in parallel than in series.

Animals↗
PubMed1996

Therapeutic immunization against Helicobacter mustelae in naturally infected ferrets.

BACKGROUND & AIMS: Helicobacter infection of the gastric antrum is responsible for a number of gastric disorders. Antibiotic therapy is lengthy and is not always effective. It has been shown previously that oral immunization against Helicobacter felis in mice can prevent colonization after challenge. The aim of this study was to investigate the efficacy of therapeutic immunization in eradicating an established Helicobacter infection and in reducing gastritis. METHODS: Domestic ferrets, confirmed to be infected with Helicobacter mustelae by gastric endoscopy, were orally immunized with varying doses of purified Helicobacter pylori urease in combination with the mucosal adjuvant cholera toxin. Ferrets were assessed 1 week and 6 weeks after treatment for infection and pathology. RESULTS: Therapeutic immunization eradicated Helicobacter colonization in 30% of all immunized ferrets, although there was no difference in efficacy between the varying doses of antigen tested. The difference was statistically significant when compared with animals administered cholera toxin alone or buffer (P = 0.04). The intensity of inflammation was also significantly reduced in immunized animals (P = 0.0003). CONCLUSIONS: Oral immunization with purified H. pylori urease and cholera toxin can eradicate H. mustelae in a natural host pathogen model. Oral immunization of chronically infected animals markedly reduced gastric inflammation.

Administration, Oral↗
PubMed2001

Site of action of GABA(B) receptor for vagal motor control of the lower esophageal sphincter in ferrets and rats.

BACKGROUND & AIMS: Stimulation of gamma-aminobutyric acid B metabotropic receptors (GBRs) by baclofen reduces the incidence of transient lower esophageal sphincter (LES) relaxations. The GBR effect may be a result of a central site of action in the dorsal vagal complex, where upper gastrointestinal vagal reflexes are integrated. Therefore, we first localized GBR immunostaining in the dorsal vagal complex. Next, we tested the hypothesis that baclofen modulates LES motor tone via GBR expressed by vagal efferent neurons. METHODS: An antibody against the human GBR1b isoform was characterized and used for immunocytochemistry in rats and ferrets. Functional studies involved microinjection of L-glutamate into the caudal dorsal motor nucleus of the vagus to evoke an LES relaxation in decerebrate unanesthetized ferrets. RESULTS: In both species, GBR1b was expressed in preganglionic motor neurons and, in ferrets, the receptor was highly expressed in identified LES-projecting preganglionic neurons. GBR1b immunostaining was also pronounced in the subnucleus centralis of the nucleus tractus solitarius. This distribution implicates GBR in control of the esophageal phase of swallowing at the level of the central program generator. In functional studies, centrally evoked LES relaxation (-73% +/- 8% mm Hg) was significantly attenuated after 7 micromol/kg intravenous baclofen (-37% +/- 10%; N = 5). CONCLUSIONS: These data all suggest that GBR agonists inhibit LES relaxation via a site of action associated with vagal motor outflow to the LES.

Amino Acid Sequence↗
PubMed1998

Overrepresentation of horizontal and vertical orientation preferences in developing ferret area 17.

One of the fundamental principles of visual cortical organization is that neurons form a "map" in which neighboring cells have similar orientation preferences. Previous anatomical and imaging studies have shown that although the exact layouts of these orientation preference maps vary between individuals, features of iso-orientation domains such as width and spacing appear constant within a species. Using chronic optical imaging of intrinsic signals we now demonstrate that in ferret area 17 a larger proportion of cortical surface is dominated by responses to horizontal and vertical contours than to the two oblique orientations. This was true for all ferrets studied both during development and in adulthood. Interestingly, however, we found that the degree of the overrepresentation varied significantly between individual animals. In some young ferrets, responses to horizontal and vertical stimuli developed faster than responses to oblique stimuli, and a much larger percentage of the cortex responded preferentially to horizontal and vertical stimuli. In other individuals, responses to all stimuli developed at roughly the same rate, and there was relatively little overrepresentation of horizontal and vertical preferences.

Aging↗
PubMed1996

Demodicosis in ferrets (Mustela putorius furo).

This report describes the clinical signs, diagnosis, and therapy of demodicosis in ferrets. Two ferrets (Mustela putorius furo) were presented with a history of local alopecia and pruritus after repeated treatment with a glucocorticoid-containing ointment for recurrent ear mite infections. Skin scrapings and biopsies revealed adult mites and larvae of Demodex spp., which were measured according to current classification techniques. Treatment with amitraz was effective and did not cause noticeable side effects. To the authors' knowledge this is the first report of demodicosis in ferrets.

Alopecia↗
PubMed1994

High concentrations of vitamin A esters circulate primarily as retinyl stearate and are stored primarily as retinyl palmitate in ferret tissues.

OBJECTIVE AND METHODOLOGY: We determined the kinds and amounts of vitamin A compounds (retinol and various retinyl esters) circulating in serum and stored in liver and other selected tissues of ferrets, using high-performance liquid chromatography. RESULTS: The concentration of total retinyl esters in serum (43 +/- 1 mumol/L, mean +/- SEM) was 25 times greater than that of retinol (1.7 +/- 0.2 mumol/L). In serum, 56% of retinyl esters was retinyl stearate, 33% was retinyl palmitate, and 5% was retinyl oleate. In contrast, in liver, vitamin A was stored primarily as retinyl palmitate (51%); smaller amounts of retinyl oleate (19%) and retinyl stearate (16%) were found. In kidneys, adrenals, small intestine, adipose tissue, skin, stomach, and eyes, retinyl palmitate was also the predominant retinyl ester, followed by retinyl stearate. In colon, lungs, and bladder, equal amounts of retinyl palmitate and retinyl stearate were observed. Other retinyl esters present in smaller amounts in most of these tissues were retinyl oleate, retinyl linoleate and/or -myristate, retinyl heptadecanoate, retinyl arachidonate, and retinyl laurate. CONCLUSIONS: Thus, the primary form of vitamin A that circulates in the blood of ferrets is retinyl stearate, whereas the primary storage form of the vitamin in tissues is retinyl palmitate. Concentrations of total vitamin A in ferret serum and other tissues were 3-73 times greater than those reported for their corresponding human tissues.

Animals↗
PubMed1997

Exposure to ionizing radiation increases responsiveness to neural secretory stimuli in the ferret jejunum in vitro.

Experiments were designed to determine the effects of ionizing radiation on jejunal epithelial function in the ferret in vitro. Basal and stimulated electrolyte transport were determined in Ussing chambers at 0.5, 2, 24 and 48 h post-irradiation. Tissue histamine and 5-hydroxytryptamine levels were measured. Myeloperoxidase activity was also measured as an index of inflammation. Basal short circuit current was reduced at 2 h post-irradiation, but was elevated at 48 h. Basal conductance was significantly increased by 24 and 48 h. Responsiveness to electrical field stimulation was depressed at 0.5 h, and was greater than control by 24 and 48 h post-irradiation. Similarly, short circuit current responses to prostaglandin E2 were depressed at 0.5 h and elevated at 24 h. No significant change was observed in the response to carbachol post-irradiation, indicating that alterations in responsiveness were not likely at the level of the enterocyte. Changes in responsiveness to electrical field stimulation correlated significantly with increases in mucosal mast cell numbers. Myeloperoxidase activity, indicative of neutrophil infiltration, did not increase post-irradiation, nor was there histological evidence of an inflammatory cell infiltrate. There were no changes in tissue histamine or 5-hydroxytryptamine. Histology also revealed little microscopic morphological change from shams in tissue from irradiated ferrets. The results of this study demonstrate effects of irradiation on electrolyte transport in the ferret jejunum. The enhanced neurally evoked electrolyte transport observed at 24-48 h post-irradiation was not correlated with the development of inflammation, but was correlated with changes in mast cell numbers.

Animals↗
PubMed1994

Effects of nitrogen dioxide on respiratory tract clearance in the ferret.

During growth and development, young children are periodically exposed to relatively high concentrations of various air contaminants, including tobacco smoke and environmental pollutants generated by fossil fuel use. The effects of these exposures on respiratory function and lung development are difficult to determine because of interindividual variation and lack of accurate dosimetry. To provide information on the effects of chronic exposure to a common indoor and outdoor pollutant during lung development, a study was performed to assess the effects of exposure to two concentrations of nitrogen dioxide (NO2; 0.5 or 10 ppm) on tracer particle clearance from the airways of ferrets exposed during postnatal respiratory tract development. Separate groups of ferrets were exposed nose-only to the test atmospheres or clean air 4 h/d, 5 d/wk, for either 8 or 15 wk. Those animals exposed for 8 wk were subsequently housed in a filtered air environment until the particle clearance measurements commenced at 3 wk prior to the end of the 15-wk exposure protocol. Radiolabeled (51Cr) tracer particles were deposited in the respiratory tract of all animals by inhalation, and the clearance rates from the head and thoracic regions were separately monitored for 18 d. No significant effects of the NO2 exposure on head airways clearance were seen. In contrast, the rates of particle clearance from the thorax of both the 8- and 15-wk groups exposed to 10 ppm NO2 were significantly reduced, and did not differ from each other. Thoracic clearance was also reduced in animals exposed to 0.5 ppm, but the rate was not significantly different from that of the clean air exposed controls. These results show that NO2 at moderate concentrations caused highly significant changes in the deep lung of the juvenile ferret, and suggest that impairment of the clearance function may be only slowly recovered after chronic exposure.

Animals↗
PubMed1999

Distinct transient outward potassium current (Ito) phenotypes and distribution of fast-inactivating potassium channel alpha subunits in ferret left ventricular myocytes.

The biophysical characteristics and alpha subunits underlying calcium-independent transient outward potassium current (Ito) phenotypes expressed in ferret left ventricular epicardial (LV epi) and endocardial (LV endo) myocytes were analyzed using patch clamp, fluorescent in situ hybridization (FISH), and immunofluorescent (IF) techniques. Two distinct Ito phenotypes were measured (21-22 degrees C) in the majority of LV epi and LV endo myocytes studied. The two Ito phenotypes displayed marked differences in peak current densities, activation thresholds, inactivation characteristics, and recovery kinetics. Ito,epi recovered rapidly [taurec, -70 mV = 51 +/- 3 ms] with minimal cumulative inactivation, while Ito,endo recovered slowly [taurec, -70 mV = 3,002 +/- 447 ms] with marked cumulative inactivation. Heteropoda toxin 2 (150 nM) blocked Ito,epi in a voltage-dependent manner, but had no effect on Ito,endo. Parallel FISH and IF measurements conducted on isolated LV epi and LV endo myocytes demonstrated that Kv1.4, Kv4.2, and Kv4.3 alpha subunit expression in LV myocyte types was quite heterogenous: (a) Kv4.2 and Kv4.3 were more predominantly expressed in LV epi than LV endo myocytes, and (b) Kv1.4 was expressed in the majority of LV endo myocytes but was essentially absent in LV epi myocytes. In combination with previous measurements on recovery kinetics (Kv1.4, slow; Kv4.2/4.3, relatively rapid) and Heteropoda toxin block (Kv1.4, insensitive; Kv4.2, sensitive), our results strongly support the hypothesis that, in ferret heart, Kv4.2/Kv4.3 and Kv1.4 alpha subunits, respectively, are the molecular substrates underlying the Ito,epi and Ito,endo phenotypes. FISH and IF measurements were also conducted on ferret ventricular tissue sections. The three Ito alpha subunits again showed distinct patterns of distribution: (a) Kv1.4 was localized primarily to the apical portion of the LV septum, LV endocardium, and approximate inner 75% of the LV free wall; (b) Kv4. 2 was localized primarily to the right ventricular free wall, epicardial layers of the LV, and base of the heart; and (c) Kv4.3 was localized primarily to epicardial layers of the LV apex and diffusely distributed in the LV free wall and septum. Therefore, in intact ventricular tissue, a heterogeneous distribution of candidate Ito alpha subunits not only exists from LV epicardium to endocardium but also from apex to base.

Amino Acid Sequence↗
PubMed1995

Electroacupuncture reduces morphine-induced emesis in ferrets: a pilot study.

We treated morphine-induced emesis in ferrets with electroacupuncture (EA) for five minutes at the acupuncture point Neiguan (P6) using two different frequencies of stimulation: 1.0 Hz and 5.0 Hz (n = 5 ferrets per group). Both EA treatments reduced the number of emetic episodes (39% reduction of episodes, p < or = 0.05 at 1.0 Hz; 43% reduction of episodes, p < or = 0.05 at 5.0 Hz) and prolonged the onset time of emesis as compared with control receiving no EA. This model demonstrates that under these conditions EA is effective as an antiemetic against morphine in the ferret and may allow for further studies on the mechanisms of acupuncture and emesis.

Analgesics, Opioid↗
PubMed1990

Nitrate biosynthesis in rats, ferrets and humans. Precursor studies with L-arginine.

L-Arginine, the primary nitrogen source for nitric oxide synthesized by many cell types in culture and for biosynthesized nitrate in humans, is also a nitrogen source for biosynthesized nitrate in rats and ferrets. After administration of [15N2]L-arginine to rats and ferrets, [15N]NO3- was detected in urine. Escherichia coli lipopolysaccharide induced more than a 10-fold increase in urinary nitrate in rats and a parallel increase in incorporation of 15N from [15N2]L-arginine into NO3-. Bradykinin, a vasodilator which induces nitric oxide production by endothelial cells in vitro, lacked detectable effect on urinary nitrate or on incorporation of L-arginine nitrogen into nitrate in rats. A prolonged period of vasodilation brought on by an extended period of exercise increased urinary nitrate 2-fold in human subjects. In the rat, recoveries in 24 h post-dose urine collections of [15N]NO3- given i.v. and i.p. were 75 and 64% respectively, while in the ferret, recoveries of i.v. and per os [15N]NO3- doses were 49 and 34% respectively. Thus, nitrate synthesized by mammalian cells in vivo would undergo losses similar to those for exogenous nitrate.

Adult↗
PubMed1986

Transport of dimethylamine, a precursor of nitrosodimethylamine, into stomach of ferret and dog.

Dimethylamine is important because it is a precursor of nitrosodimethylamine, a suspected carcinogen in man. Significant quantities of dimethylamine and nitrite are found in gastric fluid, and conditions in the stomach are favorable for nitrosodimethylamine formation. Little is known about the origins of dimethylamine in gastric fluid. Studies were performed to determine whether dimethylamine can be transported from blood to gastric fluid. There was no diurnal variation of the dimethylamine content in gastric fluid or blood from untreated dogs. We administered 50 mg/kg dimethylamine i.v. to dogs and ferrets and collected blood and gastric fluid samples at timed intervals. In both species we observed similar kinetics of dimethylamine distribution into biologic fluids. Dimethylamine concentrations in blood and gastric fluid rose rapidly during the first minutes after treatment. Blood dimethylamine concentrations peaked within 30 min after the dose (rising from 10 to 430 nmol/ml in the dogs, and from 30 to 430 nmol/ml in the ferrets). Dimethylamine concentrations in blood slowly decreased thereafter. Gastric fluid dimethylamine concentrations continued to rise for 3 h after the dose (from 40 to 540 nmol/ml in the dogs, and from 40 to 1056 nmol/ml in the ferrets). Gastric fluid dimethylamine remained elevated for more than 5 h. Between 1 h and 5 h after treatment, gastric fluid dimethylamine concentrations were significantly higher than blood dimethylamine concentrations (by greater than 2.5 X). In gastric fluid from control animals, dimethylamine concentration exceeded monomethylamine concentration, which in turn was higher than trimethylamine concentration. Administration of dimethylamine transiently increased gastric fluid monomethylamine content, but had little effect upon trimethylamine concentration. These data demonstrate that dimethylamine is efficiently transported from blood into gastric fluid.

Animals↗
PubMed2005

In vivo evidence for radial migration of neurons by long-distance somal translocation in the developing ferret visual cortex.

During the development of the cerebral cortex, neurons generated in the cortical ventricular zone migrate radially toward the marginal zone. Radially migrating neurons are thought to display 1 of 2 morphologies: cells with a long, pia-contacting, apical process utilized for somal translocation early in development, when the cortex is still relatively thin; or cells with a short leading process, abundant at late stages of corticogenesis when neurons need to travel for longer distances. In large convoluted brains, like those of many primates and carnivores, radially migrating neurons must travel distances up to several millimeters before reaching their final destination, often following curvilinear trajectories. Here we analyze modes and morphologies of radially migrating neurons in convoluted brains by studying the visual cortex of developing ferrets. We provide in vivo and in vitro evidence for the existence of late-born cortical neurons that migrate radially by long-distance somal translocation within a long apical process extended to the cortical plate, in contrast to the early somal translocation observed in rodents. Long-distance translocating neurons in the ferret show a discontinuous rhythm of migration, alternating periods of advance with periods of stall. Furthermore, by combining different labeling methods we find the simultaneous presence in the developing ferret cortex of long-distance translocating neurons and neurons migrating within a short leading process.

Adenoviridae↗
PubMed1999

The vomeronasal organ of the male ferret.

The vomeronasal organ (VNO) is known to play a major role in sexual behavior in many mammals. This study is the first report that the adult male ferret has a VNO, which is considerably smaller and morphologically different from the usually crescent-shaped epithelium in several mammalian species, particularly rodents. There were no differences in the size or structure of the ferret VNO between the mating season in spring and the sexually quiescent season in autumn, although plasma testosterone, testis size and brain size are dramatically increased in spring and behavior changes significantly. The histological data suggest that the VNO might be not as important a structure in male ferret sexual behavior as in rodents.

Animals↗
PubMed1995

Isoform diversity and tandem duplication of the glycoprotein A gene in ferret Pneumocystis carinii.

Two ferret P. carinii gpA cDNA clones were identified that reacted identically with a panel of anti-gpA monoclonal antibodies, although their nucleotide sequences were 22% divergent. Each clone hybridized to a single mRNA species of 3,600 nucleotides only in P. carinii-infected lung mRNA, but RT-PCR analysis demonstrated that these cDNA clones were derived from two distinct gpA mRNA transcripts. Further PCR analysis demonstrated that the ferret P. carinii genome contains at least two gpA genes lying in tandem on a single chromosome separated by a 329-bp intergenic region. Based on the terminal gene sequences of this tandem repeat and the cDNA clones, a composite full-length ferret P. carinii gpA coding sequence was constructed. The intergenic region immediately downstream of the stop codon of the first gpA gene contains three putative polyadenylation signals, and constitutes the 3' untranslated region (UTR) of the gpA mRNA. Primer extension of the gpA mRNA resulted in products extending 74 and 244 nucleotides into the 5' UTR. However, the intergenic region lying greater than 25 nucleotides upstream of the first methionine of the second gpA gene was found to be absent from the 5' UTR.

Amino Acid Sequence↗